The present invention relates to walking assistance devices, such as canes, crutches, and walking sticks, and is more particularly directed to such a device that includes a visual stimulation mechanism to assist a Parkinson's Disease victim in overcoming a sudden loss of mobility or motor block episode, i.e., "freezing."
Parkinson's Disease is a neurological disorder caused by imbalance of chemical messengers in the central nervous system. This disease can result in loss of control over voluntary movement in the patient. Some of the well known symptoms are resting tremor, i.e., shaking; slowness of movement or bradykinesia; muscular rigidity or stiffness; and impairment of postural righting reflexes, i.e., balance. Other symptoms may include changes in gait while walking, including shuffling of feet, short steps, difficulty with turns, and decreased arm swing on the affected side. The usual medical management strategy involves medication, and this often may lead to a satisfactory and productive quality of life. A regular exercise regimen will often be beneficial in reducing these symptoms somewhat, as the muscular and skeletal system are not directly affected by this disease, and exercise such as regular walking keeps the body healthy. However, walking can be affected by the sudden immobility or freezing.
Many people with Parkinson's Disease, or PD, periodically experience a motor block episode, often called "freezing", in which the person is suddenly made immobile, with a feeling as if his or her feet are "glued" to the floor. This can happen suddenly while walking, and can lead to loss of balance and falls. The occurrence of freezing is controlled somewhat by the patient's medication, but will occur without warning in more advanced cases, or in less advanced cases where the medication wears off. Adjusting the PD medication will not always fully solve this problem. Freezing episodes are sometimes triggered by visual stimuli, such as a change in flooring patterns, or from observing an elevator door closing or opening. Freezing occurs rather frequently when the patient is navigating through narrow passageways or small spaces. Freezing episodes will usually resolve spontaneously, but this demands time and patience. Coping with this problem can be annoying and frustrating to the PD patient. Where this happens frequently, the patient is often afraid to go out or to engage in any sort of activity on foot.
Some compensating strategies that have been tries include visualization techniques, that is, imagining a line or object on the floor, and then stepping over the imaginary object. This strategy can be successful, but requires training and concentration. Other strategies include changing the visual focus to a distant point instead of looking directly below; counting a cadence or marching in place; or rocking from side to side to break the forward "freeze."
Many PD patients carry a cane or walking stick simply to assist in balance during walking. This can also be of help if balance or strength on the affected side is affecting gait stability. However, this should usually be a straight cane or stick, as tripod or quad canes are difficult for a PD patient to use correctly.